The present invention relates to an apparatus for coloring landscaping material, and more particularly to an apparatus for coloring landscaping material incorporating a liquid atomizer.
Landscaping material includes: aggregate; stones; mulches made from wood and bark and other materials. Such landscaping material is used for many gardening and landscaping applications and is commonly made from grinding, chopping or otherwise reducing material into the form of chips or granular or particulate matter. The marketability of such products, particularly for decorative landscaping purposes, depends greatly on the appearance of the product and in particular on the color of the product.
Coloring agents have been used to artificially color landscaping material to increase marketability. The coloring agents allow for greater control and uniformity in the appearance of the product. The coloring agents commonly used include solutions in concentrated form having the desired coloring pigment which are mixed with water prior to introduction to landscaping material to be colored. The coloring mixture may also include additional admixtures such as resins and other surfactants.
Machines for coloring landscaping material have incorporated varying material handling systems and colorant distribution systems. U.S. Pat. No. 5,192,587 to Rondy, for example, discloses the use of a continuous auger screw for conveying wood chips through an upwardly angled trough. A basin near a lower end of the trough contains a supply of a colorant solution to immerse the wood chips prior to conveying. Excess colorant drains from the wood chips as they are conveyed up the trough. A desired object of the system is stated to be rapid processing of material. However, saturation of the wood chips by immersion in a basin is wasteful in terms of colorant usage. Also, the continuous helical surface of the auger screw, while providing for rapid conveyance of material, provides limited mixing of material during the conveyance.
In U.S. Pat. No. 5,308,653 to Rondy the immersion basin is replaced with a falling wall of liquid colorant from a slit pipe extending across the inlet to the conveyor. Also disclosed are radial projections from the auger shaft between the helical screw flight at spaced locations for agitation of the wood product being conveyed. Again, excess colorant is applied which is recaptured at a lower end of the angled conveyor. The use of projections intermediate to the rotating screw, provides only limited agitation.
U.S. Pat. No. 5,358,738 to Sawka includes a housing with rotating screw auger for conveying wood chips through the inclined trough. Colorant is applied in a first half of the conveyor immediately downstream of the inlet through the use of spaced nozzles. A second half of the conveyor is open to the atmosphere. Again, the limited agitation associated with the auger screw necessitates that significant excess colorant be applied to the wood chips being conveyed.
The colorant distribution systems and material handling systems of the prior art lead to inefficiencies in colorant usage and less than optimum colorant dispersal throughout the raw wood and/or bark materials.
It is therefore an object of the present invention to provide an apparatus for coloring landscaping material having a colorant distribution system and material handling system which preferably increases the mixing action and exposes more of the material surface to the colorant. This improvement results in increased uniformity in colorant distribution throughout the landscaping material, results in increased efficiency in colorant usage and limits moisture content of the material on discharge.
According to the present invention there is provided an apparatus for coloring landscaping material. The apparatus includes a mixing chamber having first and second elongated segments each with an internal cavity which are in communication with one another. A colorant distribution system is provided for delivery of a liquid colorant. The distribution system has first and second portions, with the first portion being within the first segment of the mixing chamber and providing delivery of colorant in the form of a liquid spray, and the second portion extending within the second segment of the mixing chamber, having a liquid atomizer to provide for delivery of colorant in aerosol form. A material handling system extends through the first and second segments for agitating, mixing and conveying landscaping material through the mixing chamber, from the first segment to the second segment and out of the chamber at the discharge.
According to one embodiment of the present invention, the material handling system includes a rotatably supported drive shaft extending through the first and second segments. A series of paddles are secured to arms that extend from the rotating shaft at various positions and are oriented to impart tangential and axial movement to the landscaping material. Various paddles are oriented to impart a forward axial movement in a downstream direction within respect to the mixing chamber and various other paddles are oriented to impart a reverse axial movement in an upstream direction.
According to an embodiment of the present invention, the paddles in the larger second segment of the mixing chamber are supported on relatively longer arms than the paddles of the first segment, resulting in increased tip speed for the paddles of the second segment, which are both rotating on the same shaft.
According to another embodiment of the present invention, the apparatus includes a flow controller between the first and second segments. The flow controller extends transversely with respect to an elongated length of the second segment, across an upper portion of the internal cavity of the second segment. The flow controller directs material from the first segment to the second segment through the lower portion of the mixing chamber. The apparatus may further include one or more secondary flow controllers transversely extending into the second segment. These secondary flow controllers preferably extend across a lower portion of the second segment for directing a flow of material through an upper portion of the chamber. Each of the flow controllers serves to restrict the flow toward the discharge, to increase agitation, and to increase residence time.
According to one embodiment of the present invention, the apparatus includes a material sensor extending into a hopper supported above the first segment of the chamber. The hopper retains a supply of landscaping material to be colored. The sensor provides a system start signal to a control unit for start up of the colorant and/or the material handling system following detection by the sensor that a level of landscaping material within the hopper has reached the sensor.